Ignition Keeps Cutting Out No Power

[juls33]

Help S2 R33

cruisin at a constant speed ie around carparks the car sudders and loses all power

and rolls for 3.4 sec then jolts back into life sometime its quite violent

what would cause an ignition/fuel? cut full loss of power

only momentary 3 -4 secs at a time

replaced o2 sensor

replaced cas

replaced afm

replaced plugs

tested coils

timed engine 15 deg

set idle

stock apart from a power fc

Edited June 4, 2007 by juls33

[juls33]

any ideas anybody??

[NJA82]

Sounds like a fuel cut to me, whats the condition of your fuel pump and injectors? What about your fuel filter ( i know its dumb but check it anyway ) Does it only do it at that specific load point? Or other areas of the tune? Have you checked your ignitor chip out? So it only does it while crusing slowly? If so sounds like a tuner hasnt tuned the first 3-4 lines of the power FC Fuel map properly, maybe has removed the fuel in those areas to avoid reversion richness... have seen it done before as strange as it sounds.

[juls33]

thanxs for the reply

umm pump is stock fuel filter is about a month old a/f are 13.2 donw to 11.9 at wot

last time i had on the dyno in feb its been doing it since then he could find the prob on the dyno

yes low load low speed say first second and third first five by five block

also has a slight surge at high speed like on the highway

where is my ignitior chip the series two have the ignitors in each coil so i would be not a coil prob ?

the numbers are 125 3x5 and then 129 to complete 5x5 block

[Cubes]

I had a similiar issue once. Was a bad connector on the afm signal wire. I previously had a safc in the car; removed the bullet connector soldered the wire and all good.

I found the problem by using the pfc's graph signal trace type option. I could see the afm signal dropping to 0v occasionally; that confirmed the problem.

[paulr33]

please answer the following

has it always been a problem or just only started occuring?

does it ever occur during acceleration?

when it does happen do you loose power (volts) too or does the engine just stall?

if you look at ETC, SENSOR SW CHECK when the problem occurs, what do you see?

i would say based on what you have described that its not tune related, it would be pretty hard to tune it like that

do all the lights go dim etc, have u got a battery guage, if so check it when the car has the problem

or even look at MONITOR, 1 CHANNEL, BATTVOLT and see what it does when the problem occurs

have u got the stock ecu?

put it in for 5 minutes and see if you can replicate the problem with it

if you can, then run stock ecu diag with consult and it should tell you straight away

[juls33]

thanxs for the reply

has been a problem since the power fc was installed (engine was transplated from another car all at the same time)

not under accel at all

batt voltage is good engine rpm just goes to zero no power you can even pump the accel pedal nothing at all

tps read a change but engine does nothing

no change with anything at time of fault

the stock ecu has other probs it runs reallt rich so that doesnt help much

it only happens at the low load low rpm when the same point is being used for say 400m rolling around car parks for example

[paulr33]

so if you hold the throttle constant does it do it ?

[juls33]

yes thats the time it does it constant low throttle

[juls33]

okay tries another ecu same thing so it must be engine related or some sensor fo rinput into the ecu

would changing the tps do any good ???

come on guys iv all run out of ideas

[blind_elk]

It might be a "wear spot" in the TPS which is telling the ECU that it should "fuel cut on overrun". When it happens, move the acc pedal, see if it kicks back into life. Also, try and borrow a mate's TPS and see if you can replicate the problem.

[enroe]

ive had this problem. it is most definetly the AFM.

took weeks to snoop out.

swap it with a mates and test it

[stricko]

ive had this problem. it is most definetly the AFM.

took weeks to snoop out.

swap it with a mates and test it

He said he's replaced the AFM. So unless its is another dodgy AFM and/or dodgy wiring then that isn't his problem. I have this problem with my R32 GTS-T atm and have had an ECU diagnostic tool plugged into it and the CAS reading goes crazy when it loses all power. My ECU also had an AFM fault so i cleared it and went for a drive and it came back. I'm going to change the CAS asap and will prob change to a Z32 AFM soon. You've said you have checked and replaced both of these though, there's a thread still going atm with a problem a bit like your and he changed the fuel pressure regulator and it fixed his problem so you could try that maybe. Let us know how you go mate!

Cheers

Stricko

[juls33]

yeah i have replaced both the afm and the cas

a big improvment in car response when i did

however it still has the weird cut out point

when it cuts out the engine responds to no input (accel pedal)

or otherwise

it has to be a wiring fault im going to strip it down on the weekend

[ER33CTION.]

same.

[SXR]

check the harness plug on the PFC, because they do tend to bow

[_x_FiReStOrM_x_]

I'm having this exact same problem... just wondering if you ever solved it, and if so what the fault was?

[sweetr33]

yeah i had similar problem and it was the harness plug on side of ecu not being straight, 10mm bolt was done up tight but it tends to bow like sxr said.... loosened the bolt and straightened the plug, pushed it on hard at both ends as i was doing bolt up and no problems... mate had same sympton but different overall problem, his was dodgy afm signal wire connection, kinda doesnt like when u twine the wires together n tape em up, so i stripped it all back and put connectors on it and no problem...